Mrsilico, I too have replaced the hood pad on my 1989 300SE with much success. All the advice given is accurate, so there is nothing new to add in terms of the hood pad. I would like to comment on the noise level in general. It has been my personal observation that older MBs, which yours can be considered, are not as "quiet" as the cars of today. Of course, quiet is relative and objective, but new cars are noticeably quieter. The Japanese car companies raised the bar on this issue, and consumers demand it today.
On another front, as a car ages its sound deadening materials tend to disintegrate. Just as the hood pads tend to go, so does the sound deadening at the firewall and elsewhere.
Enjoy your MB.